(1) Field of the Invention
This present invention relates to a treatment method for the hydrophilication of synthetic resin object. This invention also relates to a hydrophilication treatment method by lowering a contact angle of the surface of synthetic resin object with water.
The present invention further relates to culture devices or inspection apparatus such as vessels for tissue culture and microorganism incubation. More particularly, it relates to the culture devices such as vessels for tissue culture and microorganism incubation or inspection apparatus and manufacturing method of the same by lowering the contact angle with water or an aqueous solution (hereinafter referred to as water) on the surface of aforesaid devices and apparatus with water.
This invention uses inexpensive equipment, dry treatment method and a simple process, and continuously provides various synthetic resin devices having uniformly treated surfaces, for example, dishes, bottles, slide and cover glasses, pipettes, diluter tips and further measuring vessels for general purpose.
(2) Description of the Prior Art
Tissue culture vessels represented by dishes, trays and bottles for the tissue culture cannot plate cells to be cultured on the vessel surface unless the contact surface of the above vessels with a medium is hydrophilic. Therefore conventional vessels are unsuitable for observing the growing conditions of afore-mentioned cells, morphology of each cellular body etc. The hydrophilication treatment of these vessels by some measure has been required. Various methods have traditionally been employed for the hydrophilication and they are substantially classified into the following three groups. One of the methods is to oxidize the resin surface by treating the resin vessels with a chromic acid mixture. Although this method of treatement is quite effective, death of cells sometimes occurs during the culture when the removal of the chromic acid mixture is unsatisfactory. Chromic acid mixture is also required to be disposed after complete neutralization because the acid causes public hazard problems by the disposal after use. In addition to such problems of waste liquid treatment, the manufacture by this method depends upon a batch process, is difficult to carry out by a continuous process and results in an increased production cost. Therefore this method has many problems.
On the other hand, a method for hydrophilicating the resin surface by coating with a hydrophilic resin has recently been developed. As the hydrophilic resin for use in this method, 2-hydroxyethyl methacrylate is applied on the surface after diluting with solvents. A method has also been reported wherein methyl methacrylate is applied and successively hydrolyzed with lactic acid. The method for coating the hydrophilic resin, however, has problems on the adhesion to vessels with the hydrophilic resin. The hydrophilic resin is apt to flake off from the vessels during use and there are many cases which are difficult to adapt to practical application. Even though flaking does not occur, a drying step is required after coating . It is very difficult to uniformly coat on the vessel surface depending upon the drying method and the resulting products have also problems on the with uniformity.
In addition, there is a method for imparting to the vessel a surface hydrophilic property by plasma etching with a plasma generator. In this method, the plasma generator is expensive. Furthermore the plasma etching requires removal or exchange of the gas in the equipment, takes much time for conducting the treatment and has disadvantage of low manufacturing efficiency and high treatment cost due to the batch process.